diff --git a/app/render/backend/audiorenderworker.cpp b/app/render/backend/audiorenderworker.cpp
index b60417c37..c8d53c8b1 100644
--- a/app/render/backend/audiorenderworker.cpp
+++ b/app/render/backend/audiorenderworker.cpp
@@ -100,7 +100,7 @@ NodeValueTable AudioRenderWorker::RenderBlock(const TrackOutput *track, const Ti
 
     {
       // Save waveform to file
-      Block* src_block = static_cast<Block*>(copy_map_->value(b));
+      Block* src_block = static_cast<Block*>(copy_map_->key(b));
       QDir local_appdata_dir(Config::Current()["DiskCachePath"].toString());
       QDir waveform_loc = local_appdata_dir.filePath(QStringLiteral("waveform"));
       waveform_loc.mkpath(".");